Apparatus for use in the production of pulp from lignocellulose containing material



Oct. '7,v 1969 R. B. REINHALL 3,471,366

v APPARATUS FOR USE IN THE PRODUCTION OF PULP FROM LIGNOCELLULOSE CONTAINING MATERIAL Original Filed Oct. 18, 1963 2 SheetQs-Shet 1 3,471,366 LP FRQM' 2 Sheng-sheet 2 REINHALL sev' P.

Oct. 7, 1969 f APPARATUS FOR USE IN' THE PRODUCTION OF PU LIGNOCELLULOSE CONTAINING MATERIAL Original Filed Oct. 18, 1963 Fig. 3

United States Patent O 3,471,366 APPARATUS FOR USE IN THE PRODUCTION OF PULP FROM LIGNOCELLULOSE CONTAINING MATERIAL Rolf B. Reinhall, Lidingo, Sweden, assignor to Deibrator Aktiebolag, Stockholm, Sweden, a corporation of Sweden Continuation of application Ser. No. 317,282, Oct. 18, 1963. This application Feb. 7, 1968, Ser. No. 703,792 Claims priority, applicatilon Sweden, Jan. 8, 1963, 19 63 Int. Cl. D21c 7/00 U.S. Cl. 162-237 6 Claims ABSTRACT OF THE DISCLOSURE An apparatus for use in the continuous production of pulp from lignocellulose-containing material. The apparatus includes three containers which are used for the treatment of the lignocellulose-containing material in steam. A particular type of conveying means is used between the first container and the second container to compress the water and air from the material after it has been treated in steam n the iirst container. The compressed material is then delivered to the bottom portion of the second container where it expands and is cornpletely impregnated with liquid present in the second container. The second container is located within the third container. The third container includes means for producing a high pressure atmosphere of steam for treating the material after it has been allowed to expand and become impregnated in the second container.

BACKGROUND OF THE INVENTION This application is a continuation of Ser. No. 317,282 tiled Oct. 18, 1963, and now abandoned.

This invention relates to an apparatus for use in the continuous production of pulp from lignocellulose containing material, in the yfirst instance wood, most suitably in the shape of chips, but also from grass of various kinds, straw, sugar-cane residues and like material. The fibre pulp is intended to be used in the paper making industry or for manufacture of fibre board and building elements or other objects containing such pulp.

It is known to introduce wood chips or the like material into a first container and to there subject them to a pretreatment by steam of low pressure and corresponding relatively low temperature. Between this container and a second container having an intake conduit for an impregnating liquid there is provided at the base portion of said containers a channel or tube containing a screwconveyer which in collaboration with a counterpressure member produces a powerful mechanical pressure acting on the pretreated chips for removal of air and free water from the pores thereof. The material is relieved from said very high mechanical pressure in the second container where it is allowed to expand towards its original volume. The material is introduced below the liquid level in the container. A large quantity of impregnating liquid is sucked into the pores of the material. The second container communicates in turn with a third container in which the impregnated chips are subjected to cooking in a steam 3,471,366 Patented Oct. 7, 1969 ICC and/or liquid phase under high pressure. The pretreatment temperatures ranges between 60 and 100 C. and more and the vapour pressure during the cooking step may amount to about 8 to 10 kilograms per square centimeter. An apparatus of this type is described in the copending patent application Ser. No. 237,911, filed Nov. 15, 1962, and now abandoned, by Arne Johan Arthur Asplund.

`One main object of the invention is to provide an apparatus of the kind set forth above which is simpler in construction and therefore cheaper in manufacture and maintenance while at the same time the treatment of the raw material is improved. According to one main feature of the invention the second container is disposed within the third container and communicates with this latter at its top portion.

Even if the starting material is preheated in the rst container it has a lower temperature than that which prevails in the third container. Due to the communication between the second and the third containers thus the law of the cold wall is applicable until the freshly introduced starting material has been heated to the high temperature. A further object of the invention is to provide an apparatus of the type under consideration under which the heating time is shortened and as a consequence the condensation of steam in the impregnating liquid with subsequent diluting thereof is reduced considerably.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects and advantages of the invention will become apparent from the following description, considered in connection with the accompanying drawings which form part of the specification and of which:

FIG. 1 is a vertical longitudinal section through an apparatus constructed according to the invention for impregnation and cooking of wood chips.

FIG. 2 is a section following lines 2 2 of FIG. l.

FIG. 3 is a vertical longitudinal section of a slightly modified embodiment.

DESCRIPTION OF SPECIFIC EMBODIMENT Referring to FIGS. l and 2 of the drawings reference numeral 10 denotes the rst container, numeral 12 the second container and numeral 14 the third container of the apparatus. The container 10 is suitably closed, the starting material, primarily wood chips being fed from the top through a so-called cell-feeder 16 which suitably is of the type which is described in my Patent No. 3,077,272, granted Feb. 12, 1963, to which reference is made for a more detailed disclosure. The level until which the container is filled with chips is determined by a level control device 18 of known type. Steam of low pressure is introduced into the container 10 through a conduit 20 provided with a valve 22. In the container 10 the material undergoes a preheating treatment and simultaneously part of the air present between the chips or in the pores of the wood, respectively is expelled. The cell-feeder 16 permits the air expelled in this manner to pass out of the container 10 into the surrounding atmosphere. Atmospheric or higher pressure 1may prevail in the container.

Connected to the base portion of the container 10 is a conical tube 24 which through a cylindrical tube 26 communicates with the base portion of the container 12. A

screw-feeder 28 driven by a motor 30 extends into, and is adapted to, the conical shape of the tube 24. Adjacent the inner end of the tube 26 a valve body 32 is disposed which valve body by means of a piston-rod 34 and a hydraulic servomotor 36 is adjustable relatively to the mouth of the tube. Co-operation of the screw-feeder 28 and the valve body 32 result in a mechanical compression the chips under high pressure which may amount to 20 to 30 kilograms per square centimeter and more whereby the chips are compressed and air as Well as free water present in their pores are expelled to a substantial degree. The air and the water escape through the perforated wall 38 of the tube 28 to a suitably closed chamber 40 which through a conduit 42, a pressure control member 44, and a drain 45 is in connection with the free atmosphere.

The second container 12 is open at its top and contains suitably two mutually parallel screw conveyers 46, 48 the vertical wall of the container suitably having the form of an 8 adapted to the screws as is evident from FIG. 2. The valve body 32 and the piston-rod 34 are located exactly between the screws which for this purpose have a portion cut away in correspondence to the diameter of the valve body. The screws are secured to shafts 50 and 52, respectively, and are rotated by a motor not shown.

Chemicals containing liquid of known kind is supplied to the container 12 through a pipe 54 controlled by a valve 56. These chemicals containing solution or impregnating liquid are tilled to a level which is controlled by a level controlling device 58 which is at a distance above the mouth of the tube 26 opening into the container 12. Thus when the strongly compressed chips mass arrives in the container 12 and are there relieved from the mechanical pressure, the chips will expand like a Sponge and therefore will suck chemicals containing into their pores during their transportation in an upward direction by the screws 46 and 48.

The container 12 is located in the upper portion of the container 14 and has in the illustrated embodiment a considerably less vertical extension than the container 14. Steam under high pressure such as, for example, of 8 to 10 kilograms per square centimeter is supplied to the container 14 through a conduit 68 controlled by a valve 60 arranged in the base portion of the container. The level of the chips is determined by a control device 62 which groverns the number of revolutions of two horizontal screw conveyors 64 located at the base of the container. Said control device 62 is located in spaced relation to, and below, the base of the inner container 12.

When the impregnated chips in the container 12 have reached the upper edge of the container 12 they are fed out through a distributor 66 and fall down in the container 14. The same high vapour pressure as in the container 14 also prevails in the container 12 which has an advantageous effect on the efficiency of the impregnation. The container 12 is surrounded by a steam atmosphere for which reason the chips entering from the channel 24, 26 are heated quickly to a temperature corresponding to that of the high pressure steam. For this reason, the steam will only be condensed to only a. minor degree in the impregnating liquid in the container 12 and thus retain its most suitable concentration. Due to the features of the invention, the apparatus is given a relatively compact structure and the inner container 12 need not be provided with sealing end packings which would be relatively expensive because they should be made to withstand higher interior pressures.

The pressure control device 44 serves to adjust the pressure inside the jacket 40 to the value equal to or slightly higher than the steam pressure prevailing in the container 10 when the last-mentioned pressure is higher than the atmospheric pressure. Steam from the container 10 is prevented from escaping particularly before any plug of chips has been formed by the action of the screw conveyor 28.

The embodiment illustrated in FIG. 3 is which the same reference numerals are used as in FIGS. 1 and 2 to denote equal or equivalent parts, differs from the embodiment shown in the FIGS. 1 and 2 mainly by the feature that the inner container 68 has been elongated so as to occupy substantially the whole inner length of the container 14. The conduit 26 through which the chips are fed from the container 10 into the container 68 is thus located in the lower portion of the container 14. The embodiment shown in FIG. 3 permits prolongnation of the heating time for the chips. Further, it is rendered easier to vary the length of the heating time by having the screws 46, 48 to rotate with varying speeds.

While the apparatus for use in the production of pulp from lignocellulose containing material has been shown and described in detail, it is obvious that this invention is not to be considered as being limited to the exact form disclosed, and that changes in detail and construction may be made therein within the scope of the invention, without departing from the spirit thereof.

What is claimed is:

1. An apparatus for use in the continuous production of pulp from lignocellulose-containing material cornprising:

(a) a rst container having a first intake opening for the material and a second intake opening for the admission of steam under low pressure,

(b) a second container for an impregnating liquid having an inlet opening to introduce the material below the level of the impregnating liquid and an outlet opening at the top thereof,

(c) a first conveying means extending between the lower portions of the first and second containers, said conveying means including a compressing means providing a high pressure to the material being conveyed to compress said material before introduction into said container and a means to exhaust water and air pressed out of the material by said cornpressing means,

(d) injection means located at the bottom of said second container to introduce said impregnating liquid,

(e) means regulating the level of the impregnating liquid within the second container,

(f) a third container in which the second container is disposed, the top edge of the second container being in communication with the top portion of the third container,

(g) means providing a high pressure atmosphere of steam in the third container, and

(h) a second conveying means located in the second container to move the material from the lower portion thereof, through the impregnating liquid and over the edge of the second container into the third container.

2. An apparatus as defined in claim 1 including means regulating the level of the liquid in the third container and wherein the tOP edge 0f the second container located in the third container is above the level of the liquid in the third container.

3. An apparatus as defined in claim 1 wherein the regulating means of the third container maintains the level of the liquid in the third container below the bottom of the second container so that the latter container is entirely surrounded by an atmosphere of steam.

4. An apparatus as defined in claim 1 wherein said rst conveying means includes a channel extending between the lower portions of the first and second containers and a screw conveyor operably mounted Within said chau- 5 6 nel moves the material from the iirst container References Cited through the channel into the second container. UNITED STATES PATENTS 5. An apparatus as defined in claim 4 wherein said compressing means includes a counter-pressure 1,933,017 10/1933 Janse' et al' 162-237 X member cooperating with the screw conveyor for 5 31188267 6/1965 Guerrieri 162-237 mechanically compressing the material before intro- FOREIGN PATENTS duction into the second container. 1,051,624 2/1959 Germany.

6. An apparatus as defined in claim 4 wherein said exhaust means includes a perforated Wall for the HOWARD R' CAINE Pnmary Exammer channel adjacent to the screw conveyor for the 10 U.S. C1. X.R. escape of water and air pressed out of the material. 162-18, 19, 61 

